RAJ KUMAR GOEL INSTITUTE OF TECHNOLOGY, GHAZIABAD (U.P),201003.

NON DESTRUCTIVE TESTING

Under The Supervision OfMr. ABHINAV BHARTI.

Presented By :SHIVAM GUPTA

(1203340149)

The use of noninvasive techniques to determine the integrity of a material, component or structure

or quantitatively measuresome characteristic ofan object.

i.e. Inspect or measure without doing harm.

Flaw Detection and Evaluation Leak Detection Location Determination Dimensional Measurements Structure and Microstructure

Characterization Estimation of Mechanical and Physical

Properties

Fluorescent penetrant indication

› To assist in product development › To screen or sort incoming materials› To monitor, improve or control

manufacturing processes› To verify proper processing such as

heat treating› To inspect for in-service damage

There are NDE application at almost any stage in the production or life cycle of a component.

Most basic and common inspection method.

Tools include fiberscopes, borescopes, magnifying glasses and mirrors.

• A liquid with high surface wetting characteristics is applied to the surface of the part and allowed time to seep into surface breaking defects.

• The excess liquid is removed from the surface of the part.

• A developer (powder) is applied to pull the trapped penetrant out the defect and spread it on the surface where it can be seen.

• Visual inspection is the final step in the process. The penetrant used is often loaded with a fluorescent dye and the inspection is done under UV light to increase test sensitivity.

Advantages of Liquid Penetrate Testing

1.Simplicity of operation.2.Best method for surface breaking cracks in non-ferrous metals.

  Disadvantages of Liquid Penetrate

Testing 1.Restricted to surface breaking defects only. 2.Decreased sensitivity . 3.Uses a considerable amount of consumables

The part is magnetized. Finely milled iron particles coated with a dye pigment are then applied to the specimen. These particles are attracted to magnetic flux leakage fields and will cluster to form an indication directly over the discontinuity. This indication can be visually detected under proper lighting conditions.

Advantages of Magnetic Particle Crack Detection

Simplicity of operation and application. Quantitative. Can be automated, apart from viewing. (Though modern developments

in automatic defect recognition can be used in parts of simple geometry e.g. billets and bars. In this case a special camera captures the defect indication image and processes it for further display and action)

Disadvantages of Magnetic Particle Crack

Detection Restricted to ferromagnetic materials. Restricted to surface or near surface flaws.

The radiation used in radiography testing is a higher energy (shorter wavelength) version of the electromagnetic waves that we see as visible light. The radiation can come from an X-ray generator or a radioactive source.

High Electrical Potential

Electrons-+

X-ray Generator or Radioactive Source Creates

Radiation

Exposure Recording Device

Radiation Penetrate the Sample

Top view of developed film

X-ray film

The part is placed between the radiation source and a piece of film. The part will stop some of the radiation. Thicker and more dense area will stop more of the radiation.

= more exposure

= less exposure

The film darkness (density) will vary with the amount of radiation reaching the film through the test object.

Advantages of Radiography Information is presented pictorially. A permanent record is provided which may be viewed at a

time and place Distant from the test. Useful for thin sections. Sensitivity declared on each film. Suitable for any material. Disadvantages of Radiography Generally an inability to cope with thick sections. Possible health hazard. Need to direct the beam accurately for two-dimensional

defects

High frequency sound waves are introduced into a material and they are reflected back from surfaces or flaws.

Reflected sound energy is displayed versus time, and inspector can visualize a cross section of the specimen showing the depth of features that reflect sound.

f

plate

crack

0 2 4 6 8 10

initial pulse

crack echo

back surface echo

Oscilloscope, or flaw detector screen

Gray scale image produced using the sound reflected from the front surface of the coin

Gray scale image produced using the sound reflected from the back surface of the coin (inspected from “heads” side)

High resolution images can be produced by plotting signal strength or time-of-flight using a computer-controlled scanning system.

Advantages: 1. High penetrating power, which allows the detection of flaws deep

in the part.2.High sensitivity, permitting the detection of extremely small flaws.3 Some capability of estimating the size, orientation, shape and

nature of defects. 4.Capable of portable or highly automated operation.

 Disadvantages:1. Manual operation requires careful attention by experienced

technicians2. Extensive technical knowledge is required 3. Surface must be prepared by cleaning and removing loose scale,

paint, etc, although4.scattering by test material structure can cause false indications. 5. not easily applied to very thin materials

Inspection of Raw Products Inspection Following Secondary

Processing In-Services Damage Inspection

MachiningWeldingGrindingHeat treating

Cracking Corrosion Erosion/Wear Heat Damage etc.

Special cars are used to inspect thousands of miles of rail to find cracks that could lead to a derailment.

• India has a number of bridges.

• Corrosion, cracking and other damage can all affect a bridge’s performance.

• Bridges get a visual inspection about every 2 years.

• Some bridges are fitted with acoustic emission sensors that “listen” for sounds of cracks growing.

NDT is used to inspect pipelines to prevent leaks that could damage the environment. Visual inspection, radiography and electromagnetic testing are some of the NDT methods used.

Remote visual inspection using a robotic crawler.

Radiography of weld joints.

Magnetic flux leakage inspection. This device, known as a pig, is placed in the pipeline and collects data on the condition of the pipe as it is pushed along by whatever is being transported.